Sometimes taking too much in the way of pain relief can cause headaches so if you can do without occasionally it might be an idea to try that. A lot depends on what type of headache it is too. Sometimes a tension headache can be cured by relaxation techniques. Have you had your eyes tested - could it be a result of eye problems? I used to get migraines which caused pain and nausea (down to stress and certain foods) but I now do Tai Chi which incorporates a lot of breathing exercises which help oxygen intake and I rarely get headaches now. Good luck but as Kwicky says - if it persisits see a doctor.
I used to suffer daily headaches. Even after having my eyes tested, cutting down on my tea and coffee (caffine), spending a fortune on "popping pills", I still had them.
Then I found out that most headaches are caused by being dehydrated.
Now, if I get a headache, I drink a pint of water and its gone within the hour.